Stable solid herbicide delivery systems

ABSTRACT

Herbicide delivery systems comprising a potassium salt of a herbicidal carboxylic acid coated onto a solid carrier.

BACKGROUND

Compositions containing herbicidal and plant growth modifying chemicalsare widely used in agricultural, industrial, recreational, andresidential areas worldwide. The active ingredients of such compositionsare frequently carboxylic acids, more particularly their salts. Thesecarboxylic acid salts generally have very high water solubility leadingto their use in aqueous concentrates intended for dilution in waterprior to application by spraying and also in granules for non-spray,broadcast application.

Granule (GR) products for non-spray, broadcast application may be usedfor insect, weed, fungal pathogen and nematode control and are oftenused in soil and aquatic environments. Because of the particle weight,granules used in aerial applications may pose a reduced hazard fromoff-target drift compared to aerial liquid spray applications.

In some situations, granule compositions containing salts of herbicidalcarboxylic acids require additional processing steps in order to improvetheir storage stability. Such compositions may require the use of afinal surface coating step and an additional drying step in order toprevent stickiness and caking of the granules.

SUMMARY

Provided herein are herbicide delivery systems comprising a solidcarrier and a potassium salt of a herbicidal carboxylic acid coated ontothe surface of the solid carrier. In these herbicidal delivery systems,the potassium salt of the herbicidal carboxylic acid is from about 0.1gram acid equivalent per kilogram (g ae/kg) to about 100 g ae/kg of thetotal herbicide delivery system. Additionally, in the herbicidaldelivery systems, the coated solid carrier is free flowing and does notcake during storage.

Also provided herein are methods for preparing the herbicide deliverysystems. The herbicide delivery systems are prepared by

(a) preparing an aqueous solution of a potassium salt of a herbicidalcarboxylic acid;

(b) spraying the aqueous solution of the potassium salt of theherbicidal carboxylic acid onto a granular solid carrier; and

(c) drying the resulting sprayed granular solid carrier to provide theherbicide delivery system as non-sticky, free-flowing granules.

DETAILED DESCRIPTION

Described herein are herbicide delivery systems comprising a potassiumsalt of a herbicidal carboxylic acid coated onto a solid carrier.Compositions, where the potassium salt of the herbicidal carboxylic acidis applied to the surface of the solid carrier to form coated granules,have excellent storage stability, can be produced in a simple and costeffective manner, and offer acceptable herbicidal efficacy when used tocontrol weeds in non-spray, broadcast or spot applications.

The herbicide delivery system described herein includes:

a) a solid carrier;

b) a potassium salt of a herbicidal carboxylic acid coated onto thesurface of the solid carrier; and

c) optionally, one or more inert formulation ingredients.

The potassium salt of the herbicidal carboxylic acid coated onto thesolid carrier comprises from about 0.1 gram acid equivalent per kilogram(g ae/kg) to about 100 g ae/kg of the total weight of the herbicidedelivery system. The herbicide delivery system described herein can bein the form of broadcast-type granules that are coated with one or moreof a potassium salt of a herbicidal carboxylic acid. The coated granulesof the herbicide delivery system described herein are free-flowing anddo not cake during storage.

Solid carriers in the form of granules that are suitable for use in thedescribed herbicide delivery system can be broadly separated into twocategories: inorganic and organic. Inorganic granular carriers include,for example, silicas and silicates, such as sand, talc (hydratedmagnesium silicate), palygorskites, pyrophyllites, attapulgus clay,kaolinite clay, bentonite clay, montmorillonite clay, illite clay andFuller's earth; diatomaceous earths such as diatomite, tripolite andkieselgur/kieselguhr; carbonate chemicals or minerals such as calciumcarbonate (e.g., limestone, calcite, and chalk), and calcium magnesiumcarbonate (Dolomite); sulfates such as calcium sulfate (gypsum);chlorides such as potassium chloride; oxides such as calcium oxide andmagnesium oxide; phosphate minerals such as the apatites; elementalmaterials such as sulfur; and volcanic materials such as pumice. Also,some inorganic granular solid carriers can be synthetically preparedfrom mineral materials, such as precipitated hydrated calcium silicate,precipitated calcium carbonate, and precipitated hydrated silicondioxide. Organic granular carriers may include, for example, corn cobs,pecan shells, peanut hulls, cottonseed hulls, wheat flour, soybeanflour, wood flour, walnut shell flour, lignin, citrus pulp, corn cobs,ground grains, rice hulls, soybeans, tobacco, walnut shells, and woodrecycled paper fiber, etc. In its simplest form, a granular formulationconsists of the inert granule and the pesticide. The solid carrier mayhave a specific carrying capacity for the pesticide and any additionalinert ingredients. Such a carrying capacity can be adsorptive and/orabsorptive in nature and is generally dependent on the composition ofthe solid carrier. The solid carrier will normally be selected based onthe particular application needs for the herbicide delivery system. Thesolid carriers described herein are in the form of granules that rangein size from about 100 to about 5000 microns (μm), from about 200 toabout 4000 μm, from about 300 to about 3000 μm, from about 350 to about2000 μm, from about 350 to about 1500 μm, from about 400 to about 1300μm, or from about 400 to about 1200 μm.

In some embodiments, the solid carrier for use in the describedherbicide delivery system is comprised of mineral derived inorganicgranules that have a particle size range from about 100 to about 5000μm.

In some embodiments, the solid carrier for use in the describedherbicide delivery system is comprised of limestone chips (i.e.,granules) that have a hard inert surface, are irregular in shape, andhave a particle size range from about 400 μm to about 1200 μm, wheregreater than about 80% of the chips have a particle size within thisrange.

The potassium salt of a herbicidal carboxylic acid to be coated onto thesurface of the solid carrier, e.g., granule, may be melted into aliquid, dissolved in a solvent or dispersed in a liquid, which may thenbe sprayed onto the granule. In the absence of effective ingredients,dry granules may be physically unstable and slowly breakdown forming adust or powder. In some cases, granules containing pesticide ingredientsmay stick together, e.g. cake, which can negatively impact theirhandling properties and performance. In some cases the stickiness of thegranules can be inhibited or prevented by the use of anti-cakingadditives and/or by application of an anti-sticking coating to thesurface of the coated granule.

Using the systems and methods described herein, potassium salts ofherbicidal carboxylic acids in the form of solids or liquids that are tobe coated onto the surface of the solid carrier may be formulated asbroadcast-type granules. Such herbicide delivery system granuleformulations usually contain a relatively small amount of the pesticideingredient since the granules are frequently not further diluted with acarrier solvent such as water prior to use, but are instead applied byplacement or broadcast of the granules directly onto the area ofinterest, such as for example, plant vegetation, soil or water. Onceapplied, the active ingredient contained in the herbicide deliverysystem is released to the area of application, typically upon exposureto water.

The herbicidal carboxylic acids useful in the herbicide delivery systemdescribed herein include aryl- or heteroaryl carboxylic acid compoundsof the following general formula

wherein Ar is a phenyl, pyridine, pyrimidine or quinoline groupsubstituted with one or more substituents selected from halogen, C₁-C₆alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, amino, C₁-C₆ alkylamino, anddi(C₁-C₆ alkyl)amino. Suitable herbicidal carboxylic acids for use inthe described herbicide delivery system may include aminopyralid,aminocyclopyrachlor, clopyralid, dicamba, picloram, and mixturesthereof.

In some embodiments, the herbicidal carboxylic acid for use in theherbicide delivery system described herein is picloram.

In some embodiments, the herbicidal carboxylic acids for use in theherbicide delivery system described herein are a mixture of picloram andaminopyralid.

The herbicidal carboxylic acids described herein comprise, with respectto the total herbicide delivery system, from about 0.1 g ae/kg to about100 g ae/kg, 0.1 g ae/kg to about 80 g ae/kg, 0.1 g ae/kg to about 60 gae/kg, 0.1 g ae/kg to about 50 g ae/kg, 0.1 g ae/kg to about 40 g ae/kg,0.1 g ae/kg to about 30 g ae/kg, 0.1 g ae/kg to about 25 g ae/kg, 0.1 gae/kg to about 20 g ae/kg, 0.1 g ae/kg to about 15 g ae/kg, 0.1 g ae/kgto about 10 g ae/kg, 0.1 g ae/kg to about 8 g ae/kg, 0.1 g ae/kg toabout 6 g ae/kg, 0.1 g ae/kg to about 4 g ae/kg, 0.1 g ae/kg to about 2g ae/kg, or 0.1 g ae/kg to about 1 g ae/kg. The herbicidal carboxylicacids described herein may also comprise from about 1 g ae/kg to about100 g ae/kg, 2 g ae/kg to about 80 g ae/kg, 4 g ae/kg to about 80 gae/kg, 6 g ae/kg to about 70 g ae/kg, 8 g ae/kg to about 70 g ae/kg, 10g ae/kg to about 70 g ae/kg, 10 g ae/kg to about 60 g ae/kg, 10 g ae/kgto about 50 g ae/kg, 10 g ae/kg to about 40 g ae/kg, 10 g ae/kg to about35 g ae/kg, 10 g ae/kg to about 30 g ae/kg, 10 g ae/kg to about 25 gae/kg, or 15 g ae/kg to about 25 g ae/kg, with respect to the totalherbicide delivery system.

The relative amounts of the solid carrier and the potassium salt of theherbicidal carboxylic acid used in the compositions described herein canbe described by the weight ratio of the solid carrier to the potassiumsalt of the herbicidal carboxylic acid on an acid equivalent basis (aebasis). For example, the weight ratio of the solid carrier to theherbicidal carboxylic acid, on an ae basis, useful in the compositionsdescribed herein may range from about 10,000:1 to about 10:1, from about5000:1 to about 10:1, from about 4000:1 to about 10:1, from about 3000:1to about 10:1, from about 2000:1 to about 10:1, from about 1000:1 toabout 10:1, from about 750:1 to about 10:1, from about 500:1 to about10:1, from about 250:1 to about 10:1, from about 200:1 to about 10:1,from about 150:1 to about 10:1, from about 100:1 to about 10:1, fromabout 80:1 to about 10:1, from about 60:1 to about 10:1, from about 50:1to about 10:1, from about 40:1 to about 10:1, or from about 30:1 toabout 10:1. Additional weight ratios of the solid carrier to theherbicidal carboxylic acid, on an ae basis, may range from about 55:1 toabout 40:1, from about 54:1 to about 41:1, from about 53:1 to about42:1, from about 52:1 to about 43:1, from about 51:1 to about 44:1, fromabout 50:1 to about 45:1, or from about 49:1 to about 46:1. The weightratio of the solid carrier to the herbicidal carboxylic acid, on an aebasis, may be about 500:1, 400:1, 300:1, 200:1, 100:1, 90:1, 80:1, 70:1,60:1, 50:1, 40:1, 30:1, 20:1, or 10:1, and incremental values betweenthese ratios. Additional weight ratios of the solid carrier to theherbicidal carboxylic acid, on an ae basis, may be about 55:1, 54:1,53:1, 52:1, 51:1, 50:1, 49:1, 48:1, 47:1, 46:1, 45:1, 44:1, 43:1, 42:1,41:1 or 40:1.

Also described is a method of improving the storage stability of agranular herbicidal composition containing a salt, e.g. analkanolammonium salt such as triethanolammonium, of a herbicidalcarboxylic acid, by using the potassium salt of the herbicidalcarboxylic acid to coat the surface of the granules. Such granules arefree flowing and do not cake during storage, and do not require the useof additional surface coating and drying processing steps in order toprovide adequate storage stability properties.

Also described is a method of preparing the described herbicide deliverysystem which comprises:

(1) preparing an aqueous solution of the potassium salt of theherbicidal carboxylic acid;

(2) spraying the aqueous solution of the potassium salt of theherbicidal carboxylic acid onto the granular solid carrier; and

(3) drying the resulting sprayed granular solid carrier to provide thedescribed herbicide delivery system as non-sticky, free-flowinggranules.

The described herbicide delivery system is produced in a simpler andmore cost effective manner than some granular compositions containingamine salts of herbicidal carboxylic acids that are currently on themarket. Such currently marketed compositions require an additionalsurface coating to prevent stickiness and improve flowability of thegranules which require additional processing steps, drying energy andmaterials.

The described herbicide delivery system can be prepared with additionalinert formulation ingredients such as, but not limited to: flow aids,surfactants, dyes, fertilizers, micronutrients, and many otheradditional ingredients providing functional utility.

Also described herein is a method of controlling undesirable vegetationcomprising contacting the vegetation or the locus thereof with, orapplying to the soil to control or prevent the emergence of thevegetation, a herbicidally effective amount of the herbicide deliverysystem described herein. The application of the herbicide deliverysystem to the undesirable vegetation may be done by broadcast or spotapplication. The herbicide delivery system which contains the potassiumsalt of picloram may be particularly useful for spot application for thecontrol of brushweeds and broadleaf weeds, such as ragwort, noddingthistle, gorse, inkweed, broom, hemlock, docks, sweet brier and woollynightshade, which can be found in range and pasture lands.

The herbicide delivery system described herein can also be used inconjunction with other pesticides such as, for example, herbicides,insecticides, fungicides, and plant growth regulators, and herbicidesafeners, and various mixtures and combinations of these, and the like.These mixtures and combinations may be formulated together in a singlegranule composition, or they may be formulated as separate granulecompositions, and applied together in one application or sequentially inseparate applications. Such mixtures and combinations can be designedfor application directly to weeds or their locus.

Herbicides that may be employed in conjunction with the herbicidedelivery system described herein include, but are not limited to, 2,4-D,2,4-DEB, 2,4-DEP, 2,3,6-TBA, acetochlor, acifluorfen, aclonifen,alachlor, allidochlor, alloxydim, alorac, ametridione, ametryn,amibuzin, amicarbazone, amidosulfuron, amiprofos-methyl, amitrole,ammonium sulfamate, anilofos, anisuron, asulam, atraton, atrazine,azafenidin, azimsulfuron, aziprotryne, barban, BCPC, beflubutamid,benazolin, bencarbazone, benfluralin, benfuresate, bensulfuron,bensulide, bentazone, benzadox, benzfendizone, benzipram, benzobicyclon,benzofenap, benzofluor, benzoylprop, benzthiazuron, bicyclopyrone,bifenox, bilanafos, bispyribac, borax, bromacil, bromobonil,bromobutide, bromofenoxim, bromoxynil, brompyrazon, butachlor,butafenacil, butamifos, butenachlor, buthidazole, buthiuron, butralin,butroxydim, buturon, butylate, cacodylic acid, cafenstrole, calciumchlorate, calcium cyanamide, cambendichlor, carbasulam, carbetamide,carboxazole chlorprocarb, carfentrazone, CDEA, CEPC, chlomethoxyfen,chloramben, chloranocryl, chlorazine, chlorbromuron, chlorbufam,chloreturon, chlorfenac, chlorfenprop, chlorflurazole, chlorflurenol,chloridazon, chlorimuron, chlornitrofen, chloropon, chlorotoluron,chloroxuron, chloroxynil, chlorpropham, chlorsulfuron, chlorthal,chlorthiamid, cinidon-ethyl, cinmethylin, cinosulfuron, cisanilide,clethodim, cliodinate, clomazone, cloproxydim, cloransulam, CMA, coppersulfate, CPMF, CPPC, credazine, cresol, cumyluron, cyanatryn, cyanazine,cycloate, cyclosulfamuron, cycloxydim, cycluron, cyperquat, cyprazine,cyprazole, cypromid, daimuron, dalapon, dazomet, delachlor, desmedipham,desmetryn, di-allate, dichlobenil, dichloralurea, dichlormate,diclosulam, diethamquat, diethatyl, difenopenten, difenoxuron,difenzoquat, diflufenican, diflufenzopyr, dimefuron, dimepiperate,dimethachlor, dimethametryn, dimethenamid, dimethenamid-P, dimexano,dimidazon, dinitramine, dinofenate, dinoprop, dinosam, dinoseb,dinoterb, diphenamid, dipropetryn, diquat, disul, dithiopyr, diuron,DMPA, DNOC, DSMA, EBEP, eglinazine, endothal, epronaz, EPTC, erbon,esprocarb, ethalfluralin, ethametsulfuron, ethidimuron, ethiolate,ethofumesate, ethoxyfen, ethoxysulfuron, etinofen, etnipromid,etobenzanid, EXD, fenasulam, fenoxasulfone, fenteracol, fentrazamide,fenuron, ferrous sulfate, flamprop, flamprop-M, flazasulfuron,florasulam, fluazolate, flucarbazone, flucetosulfuron, fluchloralin,flufenacet, flufenican, flufenpyr, flumetsulam, flumezin, flumiclorac,flumioxazin, flumipropyn, fluometuron, fluorodifen, fluoroglycofen,fluoromidine, fluoronitrofen, fluothiuron, flupoxam, flupropacil,flupropanate, flupyrsulfuron, fluridone, flurochloridone, flurtamone,fluthiacet, fomesafen, foramsulfuron, fosamine, furyloxyfen,glufosinate, glufosinate-P, glyphosate, halauxifen, halosafen,halosulfuron, haloxydine, hexaflurate, hexazinone, imazamethabenz,imazamox, imazapic, imazapyr, imazaquin, imazethapyr, imazosulfuron,indanofan, indaziflam, iodobonil, iodosulfuron, iofensulfuron, ioxynil,ipazine, ipfencarbazone, iprymidam, isocarbamid, isocil, isomethiozin,isonoruron, isopolinate, isopropalin, isoproturon, isouron, isoxaben,isoxachlortole, isoxaflutole, karbutilate, ketospiradox, lactofen,lenacil, linuron, MAA, MAMA, medinoterb, mefenacet, mefluidide,mesoprazine, mesosulfuron, mesotrione, metam, metamitron, metazachlor,metazosulfuron, metflurazon, methabenzthiazuron, methalpropalin,methazole, methiobencarb, methiozolin, methiuron, methometon,methoprotryne, methyl bromide, methyl isothiocyanate, methyldymron,metobenzuron, metobromuron, metolachlor, metosulam, metoxuron,metribuzin, metsulfuron, molinate, monalide, monisouron,monochloroacetic acid, monolinuron, monuron, morfamquat, MSMA,naproanilide, napropamide, naptalam, neburon, nicosulfuron,nipyraclofen, nitralin, nitrofen, nitrofluorfen, norflurazon, noruron,OCH, orbencarb, ortho-dichlorobenzene, orthosulfamuron, oryzalin,oxadiargyl, oxadiazon, oxapyrazon, oxasulfuron, oxaziclomefone,oxyfluorfen, parafluron, paraquat, pebulate, pelargonic acid,pendimethalin, penoxsulam, pentachlorophenol, pentanochlor, pentoxazone,perfluidone, pethoxamid, phenisopham, phenmedipham, phenmedipham-ethyl,phenobenzuron, phenylmercury acetate, picolinafen, pinoxaden,piperophos, potassium arsenite, potassium azide, potassium cyanate,pretilachlor, primisulfuron, procyazine, prodiamine, profluazol,profluralin, profoxydim, proglinazine, prometon, prometryn, propachlor,propanil, propazine, propham, propisochlor, propoxycarbazone,propyrisulfuron, propyzamide, prosulfalin, prosulfocarb, prosulfuron,proxan, prynachlor, pydanon, pyraclonil, pyraflufen, pyrasulfotole,pyrazolynate, pyrazosulfuron, pyrazoxyfen, pyribenzoxim, pyributicarb,pyriclor, pyridafol, pyridate, pyriftalid, pyriminobac, pyrimisulfan,pyrithiobac, pyroxasulfone, pyroxsulam, quinclorac, quinmerac,quinoclamine, quinonamid, rhodethanil, rimsulfuron, saflufenacil,S-metolachlor, sebuthylazine, secbumeton, sethoxydim, siduron, simazine,simeton, simetryn, SMA, sulcotrione, sulfallate, sulfentrazone,sulfometuron, sulfosulfuron, sulfuric acid, sulglycapin, swep, TCA,tebutam, tebuthiuron, tefuryltrione, tembotrione, tepraloxydim,terbacil, terbucarb, terbuchlor, terbumeton, terbuthylazine, terbutryn,tetrafluron, thenylchlor, thiazafluron, thiazopyr, thidiazimin,thidiazuron, thiencarbazone-methyl, thifensulfuron, thiobencarb,tiocarbazil, tioclorim, topramezone, tralkoxydim, triafamone,tri-allate, triasulfuron, triaziflam, tribenuron, tricamba, triclopyr,tridiphane, trietazine, trifloxysulfuron, trifluralin, triflusulfuron,trifopsime, trihydroxytriazine, trimeturon, tripropindan, tritac,tritosulfuron, vernolate, and xylachlor.

Especially suitable combinations may comprise the compositions describedherein used in conjunction with one or more of 2,4-D, cloransulam,diclosulam, florasulam, flumetsulam, halauxifen, isoxaben, metosulam,penoxsulam, pyroxsulam, tebuthiuron, and mixtures thereof.

The term herbicide is used herein to mean an active ingredient thatkills, controls, or otherwise adversely modifies the growth of plants. Aherbicidally effective or vegetation controlling amount is an amount ofactive ingredient which causes an adversely modifying effect andincludes deviations from natural development, killing, regulation,desiccation, retardation, and the like. The terms plants and vegetationinclude germinant seeds, emerging seedlings, and established vegetation.

Herbicidal activity is exhibited by the compositions described hereinwhen the compositions are applied directly to the plant or to the locusof the plant at any stage of growth or before planting or emergence. Theeffect observed depends upon the plant species to be controlled, thestage of growth of the plant, the particle size of solid components, theenvironmental conditions at the time of use, the specific compoundemployed, the specific adjuvants and carriers employed, the soil type,and the like, as well as the amount of chemical applied. These and otherfactors can be adjusted as is known in the art to promote non-selectiveor selective herbicidal action.

Application rates from about 5 to about 500 grams per square meter(gm/m²) of the described herbicide delivery system may be used inbroadcast applications around or on undesirable vegetation. Generally,such applications rates may be from about 10 to about 100 gm/m². Thehigher rates designated generally provide better control of a broadvariety of undesirable vegetation some of which may be more herbicidetolerant or resistant. The lower rates are typically used for verysensitive vegetation, but may also give selective control and could, incertain cases, be employed in the locus of crops. Spot application ratesto control individual plants may be from about 1 to about 100 grams ofthe described herbicide delivery system per plant.

Surface-active agents can be incorporated into the compositionsdescribed herein. The surface-active agents can be anionic, cationic, ornonionic in character and can be employed as, wetting agents, dispersingagents, or for other purposes. Surfactants conventionally used in theart of formulation and which may also be used in the compositionsdescribed herein are described, inter alia, in “McCutcheon's Detergentsand Emulsifiers Annual”, MC Publishing Corp., Ridgewood, N.J., 1998 andin “Encyclopedia of Surfactants”, Vol. I-III, Chemical publishing Co.,New York, 1980-81. Typical surface-active agents include salts of alkylsulfates, such as diethanolammonium lauryl sulfate; alkylarylsulfonatesalts, such as calcium dodecylbenzenesulfonate; alkylphenol-alkyleneoxide addition products, such as nonylphenol-C18 ethoxylate;alcohol-alkylene oxide addition products, such as tridecyl alcohol-C16ethoxylate; soaps, such as sodium stearate; alkylnaphthalene-sulfonatesalts, such as sodium dibutylnaphthalenesulfonate; dialkyl esters ofsulfosuccinate salts, such as sodium di(2-ethylhexyl) sulfosuccinate;sorbitol esters, such as sorbitol oleate; quaternary amines, such aslauryl trimethylammonium chloride; polyethylene glycol esters of fattyacids, such as polyethylene glycol stearate; block copolymers ofethylene oxide and propylene oxide; salts of mono and dialkyl phosphateesters.

Other adjuvants commonly used in agricultural compositions includecompatibilizing agents, antifoam agents, sequestering agents,neutralizing agents and buffers, corrosion inhibitors, dyes, odorants,spreading agents, penetration aids, sticking agents, dispersing agents,thickening agents, antimicrobial agents, and the like. The compositionsof herbicidal carboxylic acids described herein may also contain othercompatible components, for example, other herbicides, plant growthregulants, fungicides, insecticides, and the like.

The compositions described herein can be applied to weeds or their locusby the use of conventional ground or aerial granule applicators, and byother conventional means known to those skilled in the art.

The following Examples are presented to illustrate various aspects ofthe compositions described herein and should not be construed aslimitations to the claims.

Example 1 Preparation of a Representative Sample of the DescribedHerbicide Delivery System—Sample 4

The herbicidal granule composition described herein was made in twosteps using the ingredients listed in Table 1. In the first step, thepreparation of the liquid aqueous phase containing the potassium salt ofthe herbicidal carboxylic acid was completed. In the second step, theliquid aqueous phase was sprayed onto the granular solid carrier andthen the resulting granules were dried to provide the describedherbicide granules.

(1) The liquid aqueous phase was prepared by adding a sufficient volumeof water to a small mixing vessel under constant agitation. Then, KOHwas added to and dissolved in the water. This creates some heat ofdissolution that requires cooling the solution to room temperature. Oncecooled, the active ingredients aminopyralid and picloram were added tothe aqueous solution of KOH. The heat of reaction between the activeingredients and the KOH was then removed by cooling. Finally, the yellowtartrazine dye was added and the resulting solution was mixed untilhomogeneous.

(2) The limestone granules (chips; 16-40 mesh) were loaded into a Munsenmixer (similar to a concrete mixer and equipped with a hot air dryer)along with the surfactant and silica. This mixture was blended togetherfor approximately 30 minutes and then the liquid aqueous phase wassprayed onto the limestone granule mixture as it was mixing. The hot airdryer was then turned on to commence the drying process which took about2.5-3 hours. After drying was complete, moisture analysis showed theproduct was sufficiently dry (<0.75 wt % water).

Samples 1, 2, 3, 5, and 6 (Table 2) were prepared in a similar manner toSample 4 except that triethanolamine (TEA) or triisopropanolamine (TIPA)were used in place of KOH for samples 1, 2, 3 and 6. Preparation ofSample 1 (Tordon™ 2G) also involved the additional steps of: (a)applying a finishing coating of Dantoin (by spraying in water) to thegranules to prevent caking and, (b) heated drying.

TABLE 1 Composition of Pic-K/AP-K Herbicidal Granule - Sample 4 ActiveIngredient Amount Granule Composition - Sample 4 Role (g ae/kg) (wt %)aminopyralid potassium (AP-K) active 0.25 0.03 picloram potassium(Pic-K) active 20.0 2.31 sodium dodecylbenzene sulphonate surfactant0.50 tartrazine dye 0.05 silica anti-caking 1.36 limestone granules(chips) solid carrier 95.05 water inert 0.70 Total 100.00

Example 2 Stability Testing of Herbicidal Granule Compositions

Test Procedure: Storage stability tests were run for 2 weeks at 47-70%relative humidity and 35-45° C. in open top glass beakers containing thetest material compressed with a glass bottle filled with silica beads toobtain a pressure of 25 g/cm² (as per CIPAC MT 172). The stored sampleswere them examined in a flowability test. This test was designed toevaluate if a granular product will remain free flowing after storageunder pressure. The test emulates storage conditions that promote cakingin the package, an undesirable attribute of a granule formulation. Fromthe flowability test results shown in Table 2, it was discovered thatthe potassium salt formulations (Samples 4 and 5) performed better thanany of the picloram alkanolamine salt granules with (Sample 1) orwithout (Samples 2, 3, 6) a Dantoin coating. The picloram TIPA saltcontaining granules prepared without a Dantoin coating (Sample 6) becameespecially hard packed after storage.

TABLE 2 Flowability Results for Herbicide Granules Stored in an ElevatedHumidity/Temperature Environment While Under Mechanical PressureFlowability Results Product or Active Standardized Sample IngredientCoated Dantoin Amount of Movements to ID # onto Granule Coating¹ CakingInitiate Flow ² 1 Tordon ™ 2G ³ Yes Minimal 3 2 Picloram-TEA No Severe -14 granules hard packed 3 Picloram-TEA No Severe - 13 and 0.25 g/kggranules aminopyralid- hard packed TEA 4 Picloram-K No Minimal 0 and0.25 g/kg aminopyralid- K. 5 Picloram-K No Minimal 0 6 Picloram - NoVery severe - >25 TIPA product did not leave the container ¹Dantoin is5,5-dimethylimidazolidine-2,4-dione polymer with formaldehyde (Lonza); ²A standardized movement is a 1 cm drop onto a hard rubber sheet; ³Tordon ™ 2G contains 3.24 wt % of picloram triethanolamine (TEA) coatedonto limestone granules which are then further coated with Dantoin (0.57wt %, dry basis).

The present invention is not limited in scope by the embodimentsdisclosed herein which are intended as illustrations of a few aspects ofthe invention and any embodiments which are functionally equivalent arewithin the scope of this invention. Various modifications of thecompositions and methods in addition to those shown and described hereinwill become apparent to those skilled in the art and are intended tofall within the scope of the appended claims. Further, while onlycertain representative combinations of the composition components andmethod steps disclosed herein are specifically discussed in theembodiments above, other combinations of the composition components andmethod steps will become apparent to those skilled in the art and alsoare intended to fall within the scope of the appended claims. Thus acombination of components or steps may be explicitly mentioned herein;however, other combinations of components and steps are included, eventhough not explicitly stated. The term “comprising” and variationsthereof as used herein is used synonymously with the term “including”and variations thereof and are open, non-limiting terms.

What is claimed is:
 1. A herbicide delivery system comprising a solidcarrier and a potassium salt of a herbicidal carboxylic acid coated ontothe surface of the solid carrier, wherein the potassium salt of theherbicidal carboxylic acid is from about 0.1 gram acid equivalent perkilogram (g ae/kg) to about 100 g ae/kg of the total herbicide deliverysystem and the coated solid carrier is free flowing and does not cakeduring storage.
 2. The herbicide delivery system of claim 1, wherein theherbicidal carboxylic acid is picloram.
 3. The herbicide delivery systemof any of claims 1-2, further comprising a second herbicidal carboxylicacid.
 4. The herbicide delivery system of claim 3, wherein the secondherbicidal carboxylic acid is aminopyralid.
 5. The herbicide deliverysystem of any of claims 1-4, wherein the herbicide delivery system is agranule or a pellet.
 6. The herbicide delivery system of any of claims1-5, further comprising one or more inert ingredients.
 7. The herbicidedelivery system of any of claims 1-6, further comprising a surfactant.8. The herbicide delivery system of any of claims 1-7, wherein the solidcarrier is limestone chips.
 9. The herbicide delivery system of any ofclaims 1-8, wherein the herbicidal carboxylic acid is a compound of theformula

wherein Ar is a phenyl, pyridine, pyrimidine or quinoline groupsubstituted with one or more substituents selected from halogen, C₁-C₆alkyl, C₁-C₆ haloalkyl, C₁-C₆ alkoxy, amino, C₁-C₆ alkylamino, anddi(C₁-C₆ alkyl)amino.
 10. The herbicide delivery system of any of claims1-8, wherein the herbicidal carboxylic acid is aminopyralid,aminocyclopyrachlor, clopyralid, dicamba, or picloram, and mixturesthereof.
 11. The herbicide delivery system of any of claims 1-10,wherein the weight ratio of the solid carrier to the herbicidalcarboxylic acid, on an acid equivalent basis, ranges from about 1000:1to about 10:1.
 12. The herbicide delivery system of any of claims 1-10,wherein the weight ratio of the solid carrier to the herbicidalcarboxylic acid, on an acid equivalent basis, ranges from about 55:1 toabout 40:1.
 13. A herbicide delivery system comprising: a solid carriercomprising from about 925 g/kg to about 975 g/kg of a solid carriercomprising limestone chips, the limestone chips having a hard inertsurface, an irregular shape; and a mixture of herbicidal carboxylicacids comprising from about 10 g ae/kg to 30 g ae/kg of a piclorampotassium salt and from about 0.1 g ae/kg to 1 g ae/kg of anaminopyralid potassium salt, wherein the mixture of herbicidalcarboxylic acids is coated onto the surface of the solid carrier and thecoated solid carrier is free flowing and does not cake during storage.14. The herbicide delivery system of claim 13, wherein greater thanabout 80% of the chips having a particle size within a range from about400 microns (μm) to about 1200 μm.
 15. A method of preparing theherbicide delivery system of claim 1 comprising: (a) preparing anaqueous solution of the potassium salt of the herbicidal carboxylicacid; (b) spraying the aqueous solution of the potassium salt of theherbicidal carboxylic acid onto a granular solid carrier; and (c) dryingthe resulting sprayed granular solid carrier to provide the herbicidedelivery system as non-sticky, free-flowing granules.